Biological membranes constitute a barrier which most hydrophilic or charged compounds cannot traverse. Encapsulation of these compounds within liposomes followed by the fusion of the liposomes with cellular membranes can be used to deliver these compounds into cells. This process is useful in delivery of drugs and for gene therapy.
Also due to their membranes, cells stay apart from each other and do not normally fuse. However for a number of applications such as for cloning and generation of hybridomas, it is necessary to fuse two cells with each other. Fusion requires merging of separate membranes into a single membrane structure, and despite efforts to facilitate the fusion with the help of chemical agents and other means such as electric shock, the efficiency of this process is generally poor. This is because the membranes have similar charges on them and thus repel each other, or the hydration shells around the lipid head groups of the membranes interfere with close contact. The two membranes have to be held together for a significant time for fusion to take place, which Brownian motion normally prevents.
An aspect of this invention is a method for improving fusion, or coalescence. of cells liposomes, lipidic particles and lipid bilayer vesicles with cells and with each other by bringing them close to each other and holding them in close proximity so that their membranes can be fused and their contents can be mixed.
Another aspect of this invention is oligonucleotide-coated liposomes containing entrapped substances for delivery into cells.
Another aspect of this invention is reagent kits containing oligonucleotide constructs useful in methods according to the invention.